Adjustable flex footwear system

ABSTRACT

Disclosed herein is a footwear system with tunable flexibility properties and a process of reversibly modifying the flexibility of footwear. In particular, there is described a footwear system comprising at least two items of footwear and at least two footwear flexibility modulators with anisotropic flexibility properties. In use, the footwear system can be reversibly switched from a stiff configuration to a flexible (i.e. less stiff) configuration. Also disclosed is a method of reversibly modulating the flexibility of footwear.

FIELD OF DISCLOSURE

The present disclosure relates to footwear, in particular to a footwear system with adjustable flexibility properties. The footwear system comprises at least two items of footwear and at least two footwear flexibility modulators with anisotropic flexibility properties. In use, the footwear system can be reversibly switched from a stiff configuration to a flexible (i.e. less stiff) configuration. Also disclosed is a method of reversibly modulating the flexibility of footwear.

BACKGROUND OF THE DISCLOSURE

Footwear for different activities has varying degrees of flexibility and support. For example, running footwear (e.g. running trainers) tends to be highly flexible to enable the foot to bend and flex through each step, but it provides low support and therefore it is not suitable for other activities such as hill walking or sports which involve side stepping, Hiking footwear tends to be stiff in order to provide support to the feet and ankles in uneven terrain. However, this support comes at the expense of flexibility and feet wearing this type of footwear are usually not allowed to perform their natural range of motion during a gait cycle.

Some activities such as hunting, trekking, scrambling, hiking or via ferrata climbing involve stepping on different types of terrain and therefore footwear having constant flexibility and support properties may not be suitable. For example, when stepping on soft terrain such as sand or soft soil, it is desirable to use footwear which enables a full range of motion of the foot, in order to minimize fatigue. Therefore, flexible footwear is desirable in soft terrain. In uneven terrain, for example in a mountain or forest, it is desirable to have stiff and supportive footwear to support the feet and ankles and minimize the risk of injuries and pain inflicted by stepping on uneven surfaces such as rocks or branches. Thus, there is a need for a footwear system with adjustable flexibility and/or support properties for use in different types of terrain.

SUMMARY OF THE DISCLOSURE

In a first aspect, there is provided a footwear system comprising:

two items of footwear, one for a left foot and one for a right foot of a user; and

at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear,

wherein each of the at least two footwear flexibility modulators has a longitudinal axis and a lateral axis perpendicular to each other, the longitudinal axis and lateral axis defining a plane of the footwear flexibility modulator,

wherein the plane has a first surface and a second surface;

wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction and a second flexural stiffness when bending in a second direction opposite the first direction, and wherein the first flexural stiffness is greater than the second flexural stiffness; and

wherein, in use, the footwear system is configured to be worn in one of two configurations:

a) a first configuration in which each of the at least two footwear flexibility modulators is disposed in, on or under at least a portion of each item of footwear with the first surface facing towards or substantially towards a collar region of each item of footwear;

b) a second configuration in which each footwear flexibility modulator is disposed in, on or under at least a portion of each item of footwear with the second surface of the footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear;

wherein the footwear flexibility modulator provides a greater resistance to bending during a gait cycle in the first configuration than in the second configuration;

and wherein the footwear system can be reversibly switched from the first configuration to the second configuration by reversing each of the footwear flexibility modulators so that, in use, the opposite of the first or second surfaces of the footwear flexibility modulator faces towards or substantially the collar region of the upper of each item of footwear.

In a second aspect; there is provided a footwear system comprising:

two items of footwear, one for a left foot and one for a right foot of a user; and

at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear,

wherein each of the at least two footwear flexibility modulators is a laminate comprising at least a first layer and a second layer joined at an interface;

wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction in which the first layer is in compression and the second layer is in tension and a second flexural stiffness when bending in a second direction opposite the first direction, in which the first layer is in tension and the second layer is in compression, and wherein the first flexural stiffness is greater than the second flexural stiffness; and

wherein, in use, the footwear system is configured to be worn in one of two configurations:

a) a first configuration in which each of the at least two footwear flexibility modulators is disposed in, on or under at least a portion of each item of footwear with the first layer facing towards or substantially towards a collar region of each item of footwear;

b) a second configuration in which each footwear flexibility modulator is disposed in, on or under at least a portion of each item of footwear with the second layer of the footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear; wherein the footwear flexibility modulator provides a greater resistance to bending during a gait cycle in the first configuration than in the second configuration;

and wherein the footwear system can be reversibly switched from the first configuration to the second configuration by reversing each of the footwear flexibility modulators so that, in use, the opposite of the first or second layers of the footwear flexibility modulator faces towards or substantially the collar region of the upper of each item of footwear,

In a third aspect there is provided a footwear system comprising at least two reversible footwear flexibility modulator inserts; each of the at least two reversible footwear flexibility modulator inserts comprising at least two layers: a first layer providing an increased bending resistance in a first bending direction relative to a bending resistance in a second bending direction, the second bending direction being opposite to the first bending direction.

In a fourth aspect, there is provided a process of reversibly modulating the flexibility of footwear, the process comprising:

-   -   a) providing two items of footwear, one for a left foot and one         for a right foot of a user;     -   b) providing at least two footwear flexibility modulators; each         of the at least two footwear flexibility modulators configured         to be removably located in, on or under at least a portion of         each of the two items of footwear,     -   wherein each of the at least two footwear flexibility modulators         has a longitudinal axis and a lateral axis perpendicular to each         other, the longitudinal axis and lateral axis defining a plane         of the footwear flexibility modulator,

wherein the plane has a first surface and a second surface;

wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction and a second flexural stiffness when bending in a second direction opposite the first direction, and

wherein the first flexural stiffness is greater than the second flexural stiffness; and

-   -   c) disposing at least one of the at least two footwear         flexibility modulators in, on or under at least a portion of         each item of footwear such that, in use, one of the first         surface or the second surface of the footwear flexibility         modulator faces towards or substantially towards a collar region         of an upper of each item of footwear;     -   d) removing the at least two footwear flexibility modulators         from the items of footwear;     -   e) reversing the at least two footwear flexibility modulators;     -   f) disposing the at least two reversed footwear flexibility         modulators in, on or under at least a portion of each item of         footwear such that, in use, the other of the first surface or         the second surface of each of the at least two footwear         flexibility modulators faces towards or substantially towards         the collar region of the upper of each item of footwear for         modifying the flexibility of the item of footwear; and     -   g) optionally, repeating steps d) to f) to revert the         flexibility properties of each item of footwear.

In a fifth aspect, there is provided a process of reversibly modulating the flexibility of footwear, the process comprising:

a) providing two items of footwear, one for a left foot and one for a right foot of a user;

b) providing at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear,

wherein each of the at least two footwear flexibility modulators is a laminate comprising at least a first layer and a second layer joined at an interface

wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction in which the first layer is in compression and the second layer is in tension and a second flexural stiffness when bending in a second direction opposite the first direction, in which the first layer is in tension and the second layer is in compression, and wherein the first flexural stiffness is greater than the second flexural stiffness; and

c) disposing at least one of the at least two footwear flexibility modulators in, on or under at least a portion of each item of footwear such that, in use, one of the first layer or the second layer of the footwear flexibility modulator faces towards or substantially towards a collar region of an upper of each item of footwear;

d) removing the at least two footwear flexibility modulators from the items of footwear;

e) reversing the at least two footwear flexibility modulator;

f) disposing the at least two reversed footwear flexibility modulators in, on or under at least a portion of each item of footwear such that, in use, the other of the first layer or the second layer of each of the at least two footwear flexibility modulators faces towards or substantially towards the collar region of the upper of each item of footwear for modifying the flexibility of the item of footwear; and

g) optionally, repeating steps d) to f) to revert the flexibility properties of each item of footwear.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to further explain the present disclosure and its advantages, a more detailed description is provided with reference to the embodiments below which are illustrated by the following Figures. It should be appreciated that these Figures relate to a typical embodiment of the disclosure and its advantages and are therefore not to be considered as limiting the scope of the disclosure, which is defined by the appended claims.

FIG. 1A shows a cross-section of a footwear flexibility modulator according to an embodiment of the disclosure in a first bent configuration (upwards) and a second bent configuration (downwards).

FIG. 1B shows a cross-section of the footwear flexibility modulator of FIG. 1A in relaxed configuration.

FIG. 2A shows a plan view of two footwear flexibility modulators according to an embodiment of the disclosure, having the first layer of the footwear flexibility modulators upwards (in use, facing towards or substantially towards a collar region of an upper of an item of footwear).

FIG. 2B shows a plan view of the two footwear flexibility modulators of FIG. 2A, having the second layer of the footwear flexibility modulators upwards (in use, facing towards or substantially towards a collar region of an upper of an item of footwear).

FIG. 2C shows a perspective view of one of the footwear flexibility modulators of FIGS. 2A and 2B, in the same configuration as in FIG. 2B, having the second layer of the footwear flexibility modulators upwards (in use, facing towards or substantially towards a collar region of an upper of an item of footwear).

FIG. 3A shows a cross-section of an item of footwear comprising a footwear flexibility modulator according to an embodiment of the disclosure. In this embodiment the footwear flexibility modulator is disposed in the sole portion of the item footwear,

FIG. 3B shows a cross-section of an item of footwear comprising a footwear flexibility modulator according to another embodiment of the disclosure. In this embodiment the footwear flexibility modulator is an insert and it is disposed on the insole and above a midsole of the item footwear.

FIG. 3C shows a cross-section of an item of footwear defining a cavity or recess in the sole for receiving a footwear flexibility modulator as described herein.

FIG. 3D shows a cross-section of the item of footwear of FIG. 3C, comprising a footwear flexibility modulator according to another embodiment of the disclosure inserted in the sole of the item of footwear. In this embodiment the footwear flexibility modulator is a sole insert and it is disposed in the sole of the item footwear.

FIG. 3E shows a longitudinal cross-section of an item of footwear according to another embodiment. The item of footwear has a longitudinal recess or cavity for receiving a footwear flexibility modulator as described herein.

FIG. 3F shows a cross-section of an item of footwear according to another embodiment. In this embodiment the item of footwear has no midsole and the footwear flexibility modulator is disposed in a recess inside the sole of the item of footwear.

FIG. 3G shows a cross-section of an item of footwear according to another embodiment. In this embodiment, the item of footwear comprises no midsole, the footwear flexibility modulator is disposed inside the upper of the item of footwear between the insole and a footbed.

FIG. 4 shows a schematic representation of a process of adjusting the flexibility of a pair of items of footwear.

FIG. 5 shows a schematic representation of a process of adjusting the flexibility of footwear, in an embodiment in which the footwear flexibility modulator is an insert disposed over an insole of an item of footwear.

FIGS. 6A to 6F show the footwear flexibility modulator of a footwear system comprising four footwear flexibility modulators.

DETAILED DESCRIPTION

Disclosed herein is a footwear system with tunable flexibility properties and a process of reversibly modifying the flexibility of footwear.

In this disclosure, there is provided a footwear system comprising:

two items of footwear, one for a left foot and one for a right foot of a user; and

at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear,

wherein each of the at least two footwear flexibility modulators has a longitudinal axis and a lateral axis perpendicular to each other, the longitudinal axis and lateral axis defining a plane of the footwear flexibility modulator,

wherein the plane has a first surface and a second surface;

wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction and a second flexural stiffness when bending in a second direction opposite the first direction, and wherein the first flexural stiffness is greater than the second flexural stiffness; and

wherein, in use, the footwear system is configured to be worn in one of two configurations:

a) a first configuration in which each of the at least two footwear flexibility modulators is disposed in, on or under at least a portion of each item of footwear with the first surface facing towards or substantially towards a collar region of each item of footwear;

b) a second configuration in which each footwear flexibility modulator is disposed in, on or under at least a portion of each item of footwear with the second surface of the footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear;

wherein the footwear flexibility modulator provides a greater resistance to bending during a gait cycle in the first configuration than in the second configuration;

and wherein the footwear system can be reversibly switched from the first configuration to the second configuration by reversing each of the footwear flexibility modulators so that, in use, the opposite of the first or second surfaces of the footwear flexibility modulator faces towards or substantially the collar region of the upper of each item of footwear.

Also disclosed herein is provided a footwear system comprising:

two items of footwear, one for a left foot and one for a right foot of a user; and

at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear,

wherein each of the at least two footwear flexibility modulators is a laminate comprising at least a first layer and a second layer joined at an interface,

wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction in which the first layer is in compression and the second layer is in tension and a second flexural stiffness when bending in a second direction opposite the first direction, in which the first layer is in tension and the second layer is in compression, and wherein the first flexural stiffness is greater than the second flexural stiffness; and

wherein, in use, the footwear system is configured to be worn in one of two configurations:

a) a first configuration in which each of the at least two footwear flexibility modulators is disposed in, on or under at least a portion of each item of footwear with the first layer facing towards or substantially towards a collar region of an upper of each item of footwear;

b) a second configuration in which each footwear flexibility modulator is disposed in, on or under at least a portion of each item of footwear with the second layer of the footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear; wherein the footwear flexibility modulator provides a greater resistance to bending during a gait cycle in the first configuration than in the second configuration;

and wherein the footwear system can be reversibly switched from the first configuration to the second configuration by reversing each of the footwear flexibility modulators so that, in use, the opposite of the first or second layers of the footwear flexibility modulator faces towards or substantially the upper of each item of footwear.

A gait cycle or stride is sequence movements during locomotion from the moment in which one foot contacts the ground to when that same foot again contacts the ground and involves propulsion of the center of gravity in the direction of motion. During a gait cycle a foot first contacts the ground (heel strike position), then rests flat (early flatfoot position), starts to bend in the plantar flex direction when the heel is lifted from the ground (early heel rise position), rests on the ball of the foot in plantar flexion with the metatarsophalangeal joint flexed (toe off position) and is completely lifted from the ground with the foot lifted upwards (dorsiflexion), before contacting the ground again in the heel strike position of the next step.

Each footwear flexibility modulator may have a longitudinal axis and a lateral axis perpendicular to each other. The longitudinal axis and lateral axis may define a plane of the footwear flexibility modulator.

The plane of the footwear flexibility modulator may have a first side and a second side. In the first configuration of the footwear flexibility modulator the first side may be disposed in, on or under each item of footwear facing towards or substantially towards a collar region of each item of footwear. In the first configuration of the footwear flexibility modulator the first side may be disposed upwards. In the second configuration of the footwear flexibility modulator the second side may be disposed in, on or under each item of footwear facing towards or substantially towards a collar region of each item of footwear. In the second configuration of the footwear flexibility modulator the second side may be disposed upwards. When the first side of the footwear flexibility modulator faces towards or substantially towards the collar region of an item of footwear, the second side of the footwear flexibility modulator faces towards or substantially towards the sole of the item of footwear. When the first side of the footwear flexibility modulator faces upwards, the second side of the footwear flexibility modulator faces downwards.

In embodiments in which the footwear flexibility modulator is a laminate with at least a first layer and at least a second layer, the at least first layer and the at least second layer of the footwear flexibility modulator may be disposed at either side of the plane of each footwear flexibility modulator.

An outermost surface of the first layer of the footwear flexibility modulator may be a first surface. An outermost surface of the second layer of the footwear flexibility modulator may be a second surface of the footwear flexibility modulator. The first surface may be disposed at an opposite side of the plane of the footwear flexibility modulator from the second surface.

The first configuration may be a stiff configuration with limited bending at the metatarsophalangeal joint region.

The second configuration may be a flexible configuration with greater flexibility at the metatarsophalangeal joint region than in the first configuration.

Each footwear flexibility modulator may be reversibly bendable along its length in two opposite directions towards the side of the first layer of the footwear flexibility modulator and/or towards the side of the second layer of the footwear flexibility modulator.

Each footwear flexibility modulator may define a relaxed configuration. In the relaxed configuration, the footwear flexibility modulator is not subjected to bending forces. In the relaxed configuration the footwear flexibility modulator may remain substantially in the plane of the footwear flexibility modulator. The footwear flexibility modulator may be substantially flat in the relaxed configuration.

The footwear flexibility modulator may define a first configuration. The first configuration may be a first bent configuration. In the first configuration, the footwear flexibility modulator may bend or flex away from the plane of the footwear flexibility modulator in a first direction. In the first configuration, the footwear flexibility modulator may bend or flex away from the plane of the footwear flexibility modulator towards or substantially towards the first side of the footwear flexibility modulator. In the first configuration, the footwear flexibility modulator may bend or flex away from the plane of the footwear flexibility modulator towards or substantially towards the side of the first layer of the footwear flexibility modulator. In other words, the footwear flexibility modulator may bend along its length towards the first side of the footwear flexibility modulator (or the side of the first layer in embodiments in which the footwear flexibility modulator is a laminate). In the first configuration, the first layer may face towards or substantially towards a collar region of an upper of each item of footwear. In the first configuration, the first layer may be in compression and the second layer may be in tension. In the first configuration, each of the two footwear flexibility modulators may be bent along its length in the direction towards the first side (or the side of the first layer in embodiments in which the footwear flexibility modulator is a laminate). In the first configuration, the first surface of the footwear flexibility modulator may be concave when looked from above. In the first configuration, the second surface of the footwear flexibility modulator may be convex when looked from below, or from the sole when in use. In the first configuration, the first surface may be concave when looked from the collar region of the upper of an item of footwear of the at least two items of footwear in, on, or under which the each of the at least two footwear flexibility modulators is disposed. In the first configuration, each of the two footwear flexibility modulators may define a first flexural stiffness. The footwear flexibility modulator in the first configuration may provide resistance to bending (i.e. flexural stiffness), for example along a longitudinal axis of the footwear flexibility modulator. The first configuration may be a stiff configuration with limited bending at the metatarsophalangeal joint region.

The footwear flexibility modulator may define a second configuration. The second configuration may be a second bent configuration. In the second configuration, the footwear flexibility modulator may bend or flex away from the plane of the footwear flexibility modulator in a second direction. In the second bent configuration, the footwear flexibility modulator may bend or flex away from the plane of the footwear flexibility modulator towards or substantially towards the side of the second surface of the footwear flexibility modulator. In other words, the footwear flexibility modulator may bend along its length towards the side of the second layer of the footwear flexibility modulator. In the second configuration, the second surface of the footwear flexibility modulator (or the second layer in embodiments in which the footwear flexibility modulator is a laminate) may face towards or substantially towards a collar region of an upper of each item of footwear. In the second configuration, in embodiments in which the footwear flexibility modulator is a laminate, the second layer may be in compression and the first layer may be in tension. In the second configuration, each of the two footwear flexibility modulators may be bent along its length in the direction towards the second surface. In the second configuration, the second surface of the footwear flexibility may be concave when viewed from above, such as from a collar region of an item of footwear when in use. In the second configuration, the first surface of the footwear flexibility modulator may be convex when viewed from below, or from the sole when in use. In the second configuration, the second surface of the footwear flexibility modulator may be concave when viewed from the collar region of the upper of an item of footwear of the at least two items of footwear in, on, or under which the each of the at least two footwear flexibility modulators is disposed. In the second configuration, each of the two footwear flexibility modulators may define a second flexural stiffness. The footwear flexibility modulator in the second configuration may provide a lower resistance to bending (lower flexural stiffness) than in the first configuration. The second configuration may be a flexible configuration with greater flexibility (or lower flexural stiffness) than in the first configuration. For example, the footwear flexibility modulator may offer lower resistance to bending (and therefore will have greater flexibility or lower flexural stiffness) in the second configuration than in the first bent configuration at the metatarsophalangeal joint region (commonly referred to as the ‘met head’), for example when bending the footwear flexibility modulator along its longitudinal axis.

The footwear flexibility modulator may present about 200% or about 250%, or about 300%, or about 350%, or about 400%, or about 450%, or about 500%, or about 550%, or about 600%, or about 650% greater resistance to bending (or flexural stiffness) in the first or stiff configuration than in the second or flexible configuration when measured in a Standard 3 or 4 point flexural stiffness/flexural tests or cantilever beam stiffness measuring methods. For example, a suitable flexural stiffness test ASTM D790 Procedure A to measure Tangent Modulus, also known as Flexural Modulus, in three point beam bending. The official test procedure for ASTM D790 is incorporated as a reference herein.

The first flexural stiffness of each footwear flexibility modulator may be from 2 times (2×) to 8 times (6×) greater than the second flexural stiffness (i.e. the flexural stiffness when bending in the direction of the second layer of the footwear flexibility modulator), when measured in a standard flexural test such as ASTM D790 Procedure A to measure Tangent Modulus, also known as Flexural Modulus, in three point beam bending. In some embodiments, the first flexural stiffness may be 2× greater, or 3× greater, or 4× greater, or 5× greater, or 6× greater than the second flexural stiffness, when measured in a standard flexural test such as ASTM D790 Procedure A to measure Tangent Modulus, also known as Flexural Modulus, in three point beam bending.

The footwear flexibility modulator may present greater longitudinal, lateral-medial and torsional flexibility in the second or flexible configuration than in the first or stiff configuration.

Each footwear flexibility modulator may be reversibly or elastically bendable along its length in two opposite directions. For example, each footwear flexibility modulator may be reversibly or elastically bendable along its length in an upwards and in a downwards direction.

The first configuration may be a stiff configuration with limited bending during a gait cycle, in particular at the metatarsophalangeal joint. The second configuration may be a flexible configuration with greater flexibility in at the metatarsophalangeal joint than in the first configuration.

In use, during a gait cycle, the footwear system comprising each item of footwear and the at least one footwear flexibility modulator coupled or attached thereto or inserted therein may bend or flex at the metatarsophalangeal joint (commonly referred to as the ‘met head’) when moving from the early flatfoot position through to the early heel rise position and to the toe off position. In the early flatfoot position, the footwear flexibility modulator may be substantially flat. In the early flatfoot position, the footwear flexibility modulator may be in the relaxed configuration. When the foot of a user moves from the early heel rise to the toe off position during a stride or gait, the footwear system may offer a first resistance to bending in the first configuration and a second resistance to bending in the second configuration. For example, during a gait cycle the flexing or bending forces on an item of footwear and/or footwear flexibility modulator coupled or attached thereto or inserted therein may be greater when the foot of a user is pointing towards a surface (e.g. the floor or a wall) and is planted on the tips of the toes and (partially) ball of the foot with the heel lifted. After heel rise, the ankle joint plantar flexes which forces the metatarsophalangeal joints into dorsiflexion. This dorsiflexion is resisted by the plantar aponeurosis, otherwise known as the plantar fascia, which supports the arch of the foot. The resistance of the plantar fascia is not to eliminate the dorsiflexion of the metatarsophalangeal joint, but rather to support the stability of the foot and arch.

The footwear flexibility modulator may have greater resistance to flexing away from the plane of the footwear flexibility modulator in the first direction than in the opposite direction. That is, the footwear flexibility modulator may present greater resistance to flexing away from the plane of the footwear flexibility modulator in the first configuration (i.e. the stiff configuration) than in the second configuration (i.e. the flexible configuration). In other words, the first flexural stiffness of each of the at least two footwear flexibility modulators may be greater than the second flexural stiffness.

The footwear flexibility modulator may comprise an anisotropic composite material. The anisotropic composite material may have two different flex moduli when the material is flexed in opposing directions. Any suitable type of anisotropic composite material may be used. For example, the footwear flexibility modulator may comprise an anisotropic composite material having at least two layers joined at their interface.

The first layer may comprise a rigid non-fibrous material. The first layer may comprise a plate with a first compressive modulus in the range of approximately 30 ksi-40,000 ksi. In some embodiments, the first layer may comprise a plate with a first compressive modulus in the range of about 30 ksi to about 40,000 ksi, or about 30 ksi to about 30,000 ksi, or about 30 ksi to about 20,000 ksi, or about 30 ksi to about 10,000 ksi, or about 30 ksi to about 5,000 ksi, or about 30 ksi to about 2,000 ksi, or about 100 ksi to about 40,000 ksi, or about 500 ksi to about 40,000 ksi, or about 1,000 ksi to about 40,000 ksi, or about 5,000 ksi to about 40,000 ksi, or about 10,000 ksi to about 40,000 ksi, or about 20,000 ksi to about 40,000 ksi, or about 30,000 ksi to about 40,000 ksi, or about 10,000 ksi to about 40,000 ksi, or about 20,000 ksi to about 30,000 ksi.

The second layer of the anisotropic composite material may comprise a fiber reinforced composite material. The second layer may comprise a fiber reinforced composite material with a second tensile modulus in the range of approximately 3 ksi-5,000 ksi. In some embodiments, the second layer may have a tensile modulus in the range of from about 2 ksi to about 3,000 ksi; from about 5 ksi to about 2,000 ksi; from about 25 ksi to about 1500 ksi; or from about 100 ksi to about 2,000 ksi.

The anisotropic material may be subjected to repeated bending and release cycles at 50% of the force required to break the material bent without breaking, cracking or permanently deforming the material. In some embodiments, the material can be flexed at 50% of the force required to break the material for 100 flex and release cycles. In other embodiments, the material can be flexed at up to 50% of the force required to break the material for 1,000 flex and release cycles without breaking, cracking or permanently deforming the material; in still further embodiments; the material can be flexed at up to 50% of the force required to break the material for 5,000 flex and release cycles without breaking, cracking or permanently deforming the material.

The footwear flexibility modulator may comprise an anisotropic composite material assembly as described in WO207095479, the content of which is incorporated herein by reference in its entirety. In particular embodiments the anisotropic composite material may be a composite material assembly commercialized under the name Carbitex AFX®.

In use, each footwear flexibility modulator may be configured to be removably coupled to, inserted in or attached to an item of footwear. The item of footwear may have an upper having a collar region for receiving, in use, a foot of a user, an insole tightly closing the upper, optionally a midsole and a sole.

A user may wear one item of footwear in the left foot and another item of footwear in the right item of footwear in the right foot.

Each footwear flexibility modulator may be shaped to conform to the shape of an insole, midsole or a sole of each of the two items of footwear. In order to reversibly switch between the first and second configuration, the footwear flexibility modulator may be configured to be turned over (in other words, overturned, reversed or inverted) and disposed in, on or under the other of the two items of footwear so that the opposite layer of each of the footwear flexibility modulator faces towards or substantially towards the collar region of the upper of the other of the two items of footwear.

The footwear flexibility modulator may be flat or substantially flat. Alternatively, the footwear flexibility modulator may be profiled to contour or receive the shape of a user's foot. For example, in embodiments in which the footwear flexibility modulator is disposed directly in contact with the foot of a user when in use, the footwear flexibility modulators may be substantially flat, and they may be profiled at a toe region.

The footwear flexibility modulators may be an insert for disposing in at least a portion of the items of footwear.

The insert may be configured to be removably disposed inside an item of footwear. The insert may be configured to be removably disposed inside the upper of an item of footwear, over an insole of the item of footwear. The insert may be placed in a pocket attached to an insole or may be otherwise attached to the insole and/or the upper. For example, in some embodiments, in use, the insert may be configured to be removably disposed between the insole of the item of footwear and the plant of the foot of a user. In other embodiments, the insert may be configured to be removably disposed between the insole of the item of footwear and a footbed. The insert, in use, may be configured to be removably disposed directly under or substantially under the plantar aspect of a foot of a user. Alternatively, in use, the insert may be configured to be removably disposed between the midsole of the item of footwear and one or more additional insoles or a footbed, and therefore it may not be in direct contact with the sole of a foot or plantar aspect of a foot of a user.

In some embodiments, the footwear flexibility modulator may be an insert disposed in a recess in a midsole of the item of footwear. The midsole insert may be configured to be removably disposed below the upper of an item of footwear, under the insole of the upper of the item of footwear. The midsole insert may be configured to be removably disposed inside an item of footwear between the sole of the item of footwear and one or more insoles.

In some embodiments, the footwear flexibility modulator may be a sole insert. The two items of footwear may define a recess or cavity configured to reversibly receive the footwear flexibility modulator. For example, the sole of each of the items of footwear may define an aperture or recess at the heel portion, and/or at one of the side portions, and/or at the front portion, the aperture configured to reversibly receive one or more footwear flexibility modulators.

The first surface, the second surface, or both first and second surfaces of the footwear flexibility modulator may be smooth or substantially smooth.

The first surface, the second surface, or both first and second surfaces of the footwear flexibility modulator may be profiled. The footwear flexibility modulator may comprise a raised profile or pattern on one or both of the surfaces of the footwear flexibility modulator. The footwear flexibility modulator may comprise a tread on one or both of the surfaces of the footwear flexibility modulator. The footwear flexibility modulator may be treaded. In embodiments in which the footwear flexibility modulator comprises a profile or a tread on both surfaces, the tread may be the same or it may be different.

The item of footwear may be selected from, but not limited to, the group comprising a shoe, a boot, a sneaker, a trainer, a wellington boot, a rubber boot, a hiking boot, a walking shoe, a trail running shoe, a snowboarding boot, a motorcycling boot, a clog, a cycling shoe, a football shoe, a football boot, a sandal, a flip-flop, a toe shoe, a climbing shoe, a running shoe, a cross-country running shoe, a hunting shoe, a hunting boot, high heeled shoe, a sky boot, a snowboard boot, and the like.

Footwear systems described herein may be particularly advantageous for activities in which different support is needed according to the load and terrain in which a user steps. For example, footwear systems described herein may be particularly advantageous for hunting.

At the beginning of a hunting expedition, a hunter may not carry heavy loads and may need to move fast and quietly to follow a pray. Footwear with increased flexibility may be required in these situations, particularly when the hunter steps on soft terrain such as mud, sand and soft soil. After hunting a pray, the hunter must carry an increased load and therefore footwear with reduced flexibility would be required for providing adequate support to the feet of the hunter. Furthermore, when a hunter steps on uneven terrain such as rocks or branches, footwear with reduced flexibility and increased support is desirable.

A footwear system as described herein has reversibly tunable flexural rigidity and therefore enables a user to adjust the flexibility and support of the footwear as required. This allows a hunter to have the optimal footwear for the entire duration of the hunting expedition without the need for carrying a spare pair of shoes.

The footwear flexibility modulator may be reversibly removable from the item of footwear. In use, the footwear flexibility modulator may be removed from an item of footwear, turned over (or reversed, inverted or overturned) and inserted in the upper or the sole of the item of footwear. This enables the flexibility properties of the item of footwear to be altered, modified or tuned.

The footwear system may comprise any suitable number of footwear flexibility modulators. For example, the footwear system may comprise 2, 4, 6, 8, 10, 12, 14, 16 or more footwear flexibility modulators.

In some embodiments, the footwear system may comprise two footwear flexibility modulators, each footwear flexibility modulator configured to be reversibly disposed in, attached to or coupled to one of the two items of footwear. In use, the flexibility of the items of footwear may be tuned by inserting/attaching/coupling at least one footwear flexibility modulators to each of the items of footwear in one of the first or second configuration, reversibly removing each footwear flexibility modulator from each item of footwear, inverting (or reversing, or overturning) each footwear flexibility modulator and inserting each footwear flexibility modulator in the other one of the two items of footwear. In other words, in order to tune the flexibility of the items of footwear, the footwear flexibility modulators are removed, flipped over and swapped, then inserted in the other one of the two items of footwear. This process may be carried out any number of times in order to tune the flexibility of the items of footwear.

In addition, the items of footwear may be worn without the footwear flexibility modulators in order to further tune the flexibility properties of the footwear system. This may be the third configuration, in which the items of footwear may have the lowest flexural rigidity.

In some embodiments, the footwear system may comprise four footwear flexibility modulators.

In these embodiments the flexibility of the items of footwear may be modulated reversibly between several combinations of the footwear system.

The first combination of the footwear system may be achieved by inserting in or coupling to each of the two items of footwear, only one footwear flexibility modulator in the first configuration (i.e. with the first surface facing towards or substantially towards the collar region of the upper of each of the items of footwear).

The second combination of the footwear system may be achieved by inserting in or coupling to each item of footwear, one footwear flexibility modulator with the second surface facing towards or substantially towards the collar region of the upper of each item of footwear. That is, in the second configuration of the footwear system, the footwear flexibility modulator is inserted in or coupled to each item of footwear in the second configuration of the footwear flexibility modulator.

A third combination of the footwear system may be achieved by removing all footwear flexibility modulators from the items of footwear. In the third configuration, the items of footwear may have the lowest flexural rigidity.

A fourth combination may be achieved by inserting in or coupling to each of the items of footwear, two footwear flexibility modulators, with the first surface of one footwear flexibility modulator facing towards or substantially towards the collar region of an upper of each item of footwear and the second layer of another footwear flexibility modulator facing towards or substantially towards the collar region of an upper of each item of footwear. In other words, in the fourth combination of the footwear system, each item of footwear comprises two footwear modulators, the uppermost footwear flexibility modulator in the first configuration of the footwear flexibility modulator, and the lowermost footwear flexibility modulator in the second configuration of the footwear flexibility modulator.

A fifth combination may be achieved by inserting in or coupling to each item of footwear, two footwear flexibility modulators, with the first surface of one footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear and the first surface of another footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear. In other words, in the fifth combination of the footwear system, each item of footwear comprises two footwear modulators, both of the footwear flexibility modulators disposed in the first configuration of the footwear flexibility modulator.

A sixth combination may be achieved by inserting in or coupling to each item of footwear, two footwear flexibility modulators, with the second surface of one footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear and the second surface of another footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear. In other words, in the sixth combination of the footwear system, each item of footwear comprises two footwear modulators, both of the footwear flexibility modulators disposed in the second configuration of the footwear flexibility modulator.

A seventh combination may be achieved by inserting in or coupling to each item of footwear, two footwear flexibility modulators, with the second surface of one footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear and the first surface of another footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear. In other words, in the seventh combination of the footwear system, each item of footwear comprises two footwear modulators, the uppermost footwear flexibility modulator disposed in the second configuration of the footwear flexibility modulator and the lowermost footwear flexibility modulator disposed in the first configuration of the footwear flexibility modulator. Without wishing to be bound by theory, the seventh combination may allow the foot of a user to bend at the metatarsophalangeal joint region while providing stability and protection from the terrain (for example when stepping on uneven terrain such as branches or stones). This may enable a user to walk comfortably when carrying heavy loads while protecting the feet from the terrain.

In some embodiments the footwear system comprises even more footwear flexibility modulators. For example, the footwear system may comprise 6, 8, 10, 12, 14, 16, 18, 20 or more footwear flexibility modulators. The footwear system may be configured to be used with any suitable number of footwear flexibility modulators.

In embodiments in which the footwear system comprises more than two footwear flexibility modulators, the two or more footwear flexibility modulators may be inserted in or coupled to each item of footwear in any suitable manner. For example, two or more footwear flexibility modulators may be inserted in or coupled to each item of footwear, with the footwear flexibility modulators disposed on top of each other. In other embodiments, one, two or more footwear flexibility modulators may be inserted inside the upper of each item of footwear, and additionally or alternatively, one, two or more footwear flexibility modulators may be inserted in or coupled to the sole of each item of footwear.

In embodiments in which more than one footwear flexibility modulator is inserted in each item of footwear, all footwear flexibility modulator may be in the first configuration or in the second configuration of the footwear flexibility modulator. In some embodiments, one or more footwear flexibility modulators may be in the first configuration of the footwear flexibility modulator and one or more footwear flexibility modulators may be in the second configuration of the footwear flexibility modulator.

In a second aspect there is provided a footwear system comprising at least two reversible footwear flexibility modulator inserts, the at least two reversible footwear flexibility modulator inserts comprising at least two layers: a first layer providing an increased bending resistance in a first bending direction relative to a bending resistance in a second bending direction, the second bending direction being opposite to the first bending direction.

Also disclosed herein, there is provided a process of reversibly modulating the flexibility of footwear, the process comprising:

-   -   a) providing two items of footwear, one for a left foot and one         for a right foot of a user;     -   b) providing at least two footwear flexibility modulators, each         of the at least two footwear flexibility modulators configured         to be removably located in, on or under at least a portion of         each of the two items of footwear,     -   wherein each of the at least two footwear flexibility modulators         has a longitudinal axis and a lateral axis perpendicular to each         other, the longitudinal axis and lateral axis defining a plane         of the footwear flexibility modulator,

wherein the plane has a first surface and a second surface;

wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction and a second flexural stiffness when bending in a second direction opposite the first direction, and wherein the first flexural stiffness is greater than the second flexural stiffness; and

-   -   c) disposing at least one of the at least two footwear         flexibility modulators in, on or under at least a portion of         each item of footwear such that, in use, one of the first         surface or the second surface of the footwear flexibility         modulator faces towards or substantially towards a collar region         of an upper of each item of footwear;     -   d) removing the at least two footwear flexibility modulators         from the items of footwear;     -   e) reversing the at least two footwear flexibility modulators;     -   f) disposing the at least two reversed footwear flexibility         modulators in, on or under at least a portion of each item of         footwear such that, in use, the other of the first surface or         the second surface of each of the at least two footwear         flexibility modulators faces towards or substantially towards         the collar region of the upper of each item of footwear for         modifying the flexibility of the item of footwear; and     -   g) optionally, repeating steps d) to f) to revert the         flexibility properties of each item of footwear;

Also disclosed herein, there is provided a process of reversibly modulating the flexibility of footwear, the process comprising:

a) providing two items of footwear, one for a left foot and one for a right foot of a user;

b) providing at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear,

wherein each of the at least two footwear flexibility modulators is a laminate comprising at least a first layer and a second layer joined at an interface

wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction in which the first layer is in compression and the second layer is in tension and a second flexural stiffness when bending in a second direction opposite the first direction, in which the first layer is in tension and the second layer is in compression, and wherein the first flexural stiffness is greater than the second flexural stiffness;

and

c) disposing at least one of the at least two footwear flexibility modulators in, on or under at least a portion of each item of footwear such that, in use, one of the first layer or the second layer of the footwear flexibility modulator faces towards or substantially towards a collar region of an upper of each item of footwear;

d) removing the at least two footwear flexibility modulators from the items of footwear;

e) reversing the at least two footwear flexibility modulator;

f) disposing the at least two reversed footwear flexibility modulators in, on or under at least a portion of each item of footwear such that, in use, the other of the first layer or the second layer of each of the at least two footwear flexibility modulators faces towards or substantially towards the collar region of the upper of each item of footwear for modifying the flexibility of the item of footwear; and

g) optionally, repeating steps d) to f) to revert the flexibility properties of each item of footwear.

When the footwear flexibility modulator is disposed with the first surface facing towards or substantially towards the collar region of the upper of the item of footwear; the item of footwear may be tuned to provide support and resistance to bending at the metatarsophalangeal joint region.

When the footwear flexibility modulator is disposed with the second surface facing the collar region of the upper of the item of footwear, the item of footwear may be tuned to provide flexibility and lower resistance to bending at the metatarsophalangeal joint region than when the footwear flexibility modulator is disposed with the first layer facing towards or substantially towards the collar region of the upper of the item of footwear.

Each of the footwear flexibility modulators may be shaped to conform to the shape of an insole, footbed, midsole or a sole of each of the two items of footwear and wherein, in order to reversibly modify the flexibility of each item of footwear, in step d) each footwear flexibility modulator may be removed from one of the two items of footwear and in step e) may be turned over and disposed in, on or under the other of the two items of footwear so that, in use, the opposite layer of the footwear flexibility modulator faces towards or substantially towards a sole of a foot of the user.

Each flexibility modulator may be an insert configured to be disposed in an item of footwear on an insole and in steps c), f) and g) it may be disposed inside each item of footwear directly on the insole.

Each flexibility modulator may be an insert and in steps c), f) and g) it may be disposed inside each item of footwear between a midsole and an insole.

Each flexibility modulator may be a sole attachment and in steps c), f) and g) it may be disposed in a recess in a sole of each item of footwear.

Each flexibility modulator may be a footbed and in steps c), f) and g) it may be disposed inside the upper, on an insole of each item of footwear.

The footwear flexibility modulator may comprise an anisotropic composite material, Any suitable type of anisotropic composite material may be used. The footwear flexibility modulator may comprise at least two layers joined together at their interface.

Any suitable type of anisotropic composite material may be used, for example laminates comprising at least one fiber reinforced layer may be used. The composite may comprise a first layer comprising a plate with a modulus of elasticity in the range of approximately 30 ksi-40,000 ksi. The composite may comprise a second layer comprising a fiber-reinforced material comprising unidirectional fibers or interlaced fibers. The second layer may have a high tensile modulus (in the range of approximately 2 ksi 3,000 ksi; about 5 ksi 2,000 ksi; about 25 ksi-1500 ksi; or about 100 ksi-2,000 ksi) and may present lower resistance to bending than the first layer. The composite fiber material of the second layer may have lower compressive modulus than the material of the first layer, such that the laminate allows a greater degree of bending in the direction of the second layer than in the direction of the first layer.

The footwear flexibility modulator may comprise an anisotropic composite material assembly as described in WO207095479, the content of which is incorporated herein by reference in its entirety. In particular embodiments the anisotropic composite material may be a composite material assembly commercialized under the name Carbitex AFX®.

In the present context, plane of the footwear flexibility modulator may be defined by the major plane of the insert which, in use, is disposed substantially parallel to the plantar aspect or sole of the foot of a user or substantially parallel to the sole of an item of footwear to which the insert is applied.

The sole of a foot or plantar aspect of a foot is the bottom of the foot.

The upper of an item of footwear is the entire part of the shoe which, in use, receives a foot of a user. In closed items of footwear such as shoes or boots, the upper of an item of footwear may be a closed bag having an opening for a foot at the top. The upper may be closed at the bottom by an insole. The sole of the item of footwear may be connected to the insole. In some embodiments, there may be a midsole between the insole and the sole. In other words, the upper of an item of footwear consists of all parts or sections of the item of footwear disposed above the sole of the item of footwear. The upper may have a collar region. The collar region of the upper may define an opening to receive, in use, a foot of a user.

The footbed is a portion of an item of footwear on which, in use a sole of a foot of a user may rest or be in contact with. The footbed is disposed inside an upper of an item of footwear. For example, a footbed may be disposed on an insole of the upper of an item of footwear. A footbed may be reversibly removable from the upper of an item of footwear.

The insole is the portion of an item of footwear which, in use, is disposed over the midsole or sole of an item of footwear and tightly closes the upper of the item of footwear. The insole may be firmly attached at least to the ends of the upper material, e.g. by gluing or sewing. Within the context of this disclosure, an insole is not removable from the upper.

The midsole is the layer of material located under the insole but over the sole or outsole. In some embodiments, an item of footwear may not comprise a midsole. The function of the midsole is to provide the main support and cushioning components to the item of footwear.

The sole or outersole of an item of footwear is the portion of the item of footwear which, in use, is configured to contact the ground.

Other aspects and embodiments of the disclosure provide the aspects and embodiments described above with the term “comprising” replaced by the term “consisting of” and the aspects and embodiments described above with the term “comprising” replaced by the term “consisting essentially of”.

It is to be understood that the application discloses all combinations of any of the above aspects and embodiments described above with each other, unless the context demands otherwise. Similarly, the application discloses all combinations of the preferred and/or optional features either singly or together with any of the other aspects, unless the context demands otherwise.

All documents mentioned in this specification are incorporated herein by reference in their entirety for all purposes.

The term “and/or” where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example, “A and/or B” or “one or both of A and B” is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein.

Certain aspects and embodiments of the disclosure will now be illustrated by way of example.

FIG. 1A shows a cross-section of a footwear flexibility modulator 10 according to an embodiment of the disclosure in a first bent configuration (upwards) and a second bent configuration (downwards).

As shown in FIG. 1A, the footwear flexibility modulator 10 can be bent in two opposite directions, but in the upwards direction (first configuration) as shown in the figure there is greater resistance to bending than in the downwards direction (second configuration).

The footwear flexibility modulator comprises an anisotropic composite material. In this embodiment, the footwear flexibility modulator 10 comprises a first layer 12 joined to a second layer 14. The outer surface A of the first layer 12 faces upwards in this figure and the outer surface B of the second layer 14 faces downwards in this figure.

Any suitable type of anisotropic composite material may be used, for example laminates comprising at least one fiber reinforced layer may be used. For example, the first layer 12 may comprise a plate with a modulus of elasticity in the range of approximately 30 ksi 40,000 ksi. The second layer 14 may comprise a fiber-reinforced material comprising unidirectional fibers or interlaced fiber. Layer 14 has a high tensile modulus (in the range of about 2-3,000 ksi; about 5-2,000 ksi; about 25-1,500 ksi; or about 100-2,000 ksi) and presents lower resistance to bending than layer 12. The composite fiber material of the second layer 14 has lower compressive modulus than the material of the first layer 12, such that the laminate allows a greater degree of bending in the downward direction than in the upward direction when disposed in the configuration shown in FIG. 1A.

FIG. 1B shows a cross-section of the footwear flexibility modulator of FIG. 1A in the relaxed configuration. The anisotropic composite material may comprise a single layer having different flexural stiffness when bending in different directions. The anisotropic composite material may comprise two layers joined together along a plane defined by a longitudinal axis and a lateral axis perpendicular to each other. The footwear flexibility modulator may comprise an anisotropic composite material assembly as described in WO207095479, the content of which is incorporated herein by reference in its entirety. In particular embodiments the anisotropic composite material may be a composite material assembly commercialized under the name Carbitex AFX®,

FIG. 2A shows a plan view of a pair of footwear flexibility modulators 20 according to an embodiment of the disclosure. The pair of footwear flexibility modulators 20 has a left footwear flexibility modulator 22 a and a right footwear flexibility modulator 22 b, both shaped to fit items of footwear (e.g. left and right shoes/boots). In this figure the left footwear flexibility modulator 22 a is shown in the plane 29 defined by a longitudinal axis 25 and a lateral axis 27 perpendicular to the longitudinal axis 25. The footwear flexibility modulators have a first surface A of the footwear flexibility modulators upwards, towards or substantially towards a collar region of an upper of the item of footwear (and in use facing towards a plantar aspect of a foot of a user).

FIG. 2B shows a plan view of the two footwear flexibility modulators of FIG. 2A, having the second surface B of the footwear flexibility modulators upwards, towards or substantially towards a collar region of an upper of the item of footwear (and in use facing towards a sole of a foot of a user). When the footwear flexibility modulators are inserted in or attached to or under items of footwear in this configuration, a user would experience resistance to bending during a gait cycle, particularly at the metatarsophalangeal joint region. Therefore, items of footwear coupled to the footwear flexibility modulators in this configuration would be relatively stiff and supportive. This would be advantageous in uneven terrain, for example in the presence of rocks or branches.

In order to exchange the shaped footwear flexibility modulators from the configuration in FIG. 2A to the configuration of FIG. 2B, a user needs to remove the footwear flexibility modulator 22 a from the left item of footwear (e.g. shoe/boot), turn it over and insert or attach the footwear flexibility modulator in or to the right item of footwear, with layer B facing upwards (towards a collar region of the item of footwear). Therefore, the footwear flexibility modulator that was inserted in or attached to one item of footwear in the first configuration has to be turned over and inserted in the opposite item of footwear in the second configuration. In this configuration, a user would experience lower resistance to bending during a gait cycle than in the first configuration shown in FIG. 2A. Therefore, in this configuration, the items of footwear modified with the footwear flexibility modulators would be more flexible than in the configuration shown in FIG. 2A. This would enable to move the feet more freely during a gait cycle and would provide more feel of the terrain than in the first configuration. This could be advantageous, for example in soft terrain such as sand and soft soil.

FIG. 2C shows a perspective view of the left footwear flexibility modulator 24 b of FIG. 2B (or right footwear flexibility modulator 22 b of FIG. 2A). In this figure the footwear flexibility modulator 24 b is shown in the same configuration as in FIG. 2B, having the second layer B of the footwear flexibility modulator upwards (in use, towards a collar region of an item of footwear).

FIG. 3A shows a cross-section of an item of footwear 100 comprising a footwear flexibility modulator 140 according to another embodiment. In this embodiment the footwear flexibility modulator 140 is disposed in the sole portion 150 of the item footwear 100. The item of footwear 100 further comprises a midsole 130, and insole 110, which in use is configured to be disposed under a sole of a foot of a user, and an upper 120 (only the insole and a portion of the material of the upper 120 joined to the insole is shown in this Figure). Although not shown, the item of footwear may further comprise a footbed disposed on top of the insole 110. The midsole 130 comprises a pocket or recess configured to removably receive the footwear flexibility modulator 140. The pocket or recess may be accessible through an aperture at the front, side or back of the item of footwear, or through a pocket in the insole 110. In use, one or more footwear flexibility modulators 140 may be inserted in the recess in order to alter the flexibility of the item of footwear.

FIG. 3B shows a cross-section of an item of footwear 200 comprising a footwear flexibility modulator 240 according to another embodiment. In this embodiment the footwear flexibility modulator 240 is an insert and it is disposed on the insole 210 over the midsole 230 of the item footwear 200, inside the upper 220 (only a portion of the upper 220 is shown). In use, the footwear flexibility modulator 240 can be the footbed or it can be disposed between the insole 210 of the item of footwear and a footbed. The item of footwear 200 also comprises a sole portion 250, which in use is configured to support the item of footwear 200 on a surface, such as the ground or a wall). The insert 240 is removable such that the footwear flexibility modulator 240 can be switched between the first (stiff) configuration (not shown) and the second (flexible) configuration, which is shown in the Figure.

FIG. 3C shows a cross-section of an item of footwear 400 (e.g. shoe or boot) defining a cavity or recess 460 in the sole for receiving a footwear flexibility modulator as described herein.

FIG. 3D shows a cross-section of the item of footwear 400 of FIG. 3C, comprising a footwear flexibility modulator 470 according to another embodiment of the disclosure inserted in the sole 450 of the item of footwear 400. In this embodiment the footwear flexibility modulator 470 is a sole insert and it is disposed in the sole 450 of the item footwear. The cavity 460 of the sole 450 may be accessed from an aperture, for example on the side, front or heel of the sole 450.

FIG. 3E shows a longitudinal cross-section of an item of footwear 500 according to another embodiment. The item of footwear is a shoe having a collar 560 in the upper an insole 510, a midsole 530 and a sole 550 having a longitudinal recess 550 for receiving a footwear flexibility modulator as described herein (not shown inside the cavity),

FIG. 3F shows a cross-section of an item of footwear 600 according to another embodiment. In this embodiment the item of footwear 600 has no midsole and the footwear flexibility modulator 660 is disposed in a recess inside the sole 650. The item of footwear also has an upper 620 which is closed by an insole 610. The item of footwear may further comprise a footbed disposed on the insole 610 (not shown).

FIG. 3G shows a cross-section of an item of footwear 700 according to another embodiment. In this embodiment, the item of footwear 700 comprises no midsole, the footwear flexibility modulator 740 is disposed inside the upper of the item of footwear between the insole and a footbed 780. In use, the flexibility of the item of footwear can be reversibly modulated by removing the footbed 780, removing the footwear flexibility modulator 740, reversing or overturning the footwear flexibility modulator 740 and inserting it in the other item of footwear 700 of a pair of items of footwear with the opposite layer facing towards the collar region of the upper of the item of footwear (and, in use, towards a sole of a foot of a user when the pair of items of footwear is worn). The process can be repeated as many times as required.

In addition, multiple footwear flexibility modulators may be used to further tune the flexibility of the footwear system. The footwear flexibility modulators may be disposed on top of each other in different configurations to tune the flexibility of the item of footwear.

FIG. 4 shows a schematic representation of a process of adjusting the flexibility of a pair of items of footwear. Shown on the left- and right-hand side of the figure are two configurations of a pair of footwear flexibility modulators 800 comprising left and right shape to match the shape of a sole portion or an insole or a midsole of left and right items of footwear.

On the left-hand side the footwear flexibility modulators 800 are shown in the second (flexible) configuration, with the surface B of the footwear flexibility modulators 800, in use facing towards or substantially towards the collar region of the upper of the items of footwear, (and in use towards the sole of a foot of a user once coupled to an item of footwear. In this configuration, the footwear flexibility modulators 800 present less resistance to bending during a gait cycle than in the first (stiff) configuration shown on the right hand side, with the surface A of the footwear flexibility modulators facing towards or substantially towards the collar region of the upper of the items of footwear, (and in use, towards the sole of a foot of a user).

In order to reversibly switch between configurations, a user would remove the footwear flexibility modulator 810 from the left item of footwear, turn it over and insert it or attach it to, on or under the right item of footwear. Similarly, the user would remove the footwear flexibility modulator 820 from the right item of footwear, turn it over and insert it or attach it to, on or under the left item of footwear. This way, the flexibility of the items of footwear can be tuned or modulated reversibly according to the user's needs. Advantageously, this enables a single pair of items of footwear to perform optimally in different terrains,

FIG. 5 shows a schematic representation of a process of adjusting the flexibility of footwear, in an embodiment in which the footwear flexibility modulator is an insert disposed over an insole of an item of footwear. In this embodiment, there is shown a cross-section of pair of items of footwear comprising a left shoe 910 and a right shoe 920. Shown on the left-hand side is the left shoe 910 with the footwear flexibility modulator 630 disposed inside the shoe 610 in the second (flexible) configuration, with the surface 914 (which presents lower resistance to bending) facing towards the collar region of the upper of the item of footwear (and towards the sole of a user in use). In order to reversibly switch to the first (stiff) configuration shown on the right-hand side, a user would remove the insert 930 from the left shoe 910, turn it over and insert it inside the right shoe 920 with the surface 912 (which offers greater resistance to bending than layer 914) facing towards the collar region of the upper of the item of footwear (and towards the sole of the right foot of a user when the modified items of footwear are worn by the user).

FIGS. 6A to 6F show the different combinations of footwear flexibility modulators that can be used in a footwear system comprising four footwear flexibility modulators. Although not shown, the footwear flexibility modulators may be inserted in the upper of the items of footwear, for example between the insole and a removable footbed.

FIG. 6A shows the first combination of the footwear system in which only one footwear flexibility modulator in the first configuration (i.e. with the first surface facing towards or substantially towards the collar region of the upper of each of the items of footwear) is inserted in each item of footwear.

FIG. 6B shows the second combination of the footwear system, in which only one footwear flexibility modulator is inserted inside the upper of the items of footwear with the second surface facing towards or substantially towards the collar region of the upper of each item of footwear. That is, in the second configuration of the footwear system, the footwear flexibility modulator is inserted in or coupled to each item of footwear in the second configuration of the footwear flexibility modulator.

A third combination of the footwear system may be achieved by removing all footwear flexibility modulators from the items of footwear (not shown in the Figure). In the third configuration, the items of footwear may have the lowest flexural rigidity.

FIG. 6C shows a fourth combination in which two footwear flexibility modulators are disposed on top of each other inside the upper of an item of footwear, for example between the insole and a removable footbed, with the first surface of one footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear and the second surface of another footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear. In other words, in the fourth combination of the footwear system, each item of footwear comprises two footwear modulators, the uppermost footwear flexibility modulator in the first configuration of the footwear flexibility modulator, and the lowermost footwear flexibility modulator in the second configuration of the footwear flexibility modulator.

FIG. 6D shows a fifth combination in which two footwear flexibility modulators are inserted inside the upper of the items of footwear one on top of the other (for example between the insole and a removable footbed), with the first surface of one footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear and the first surface of another footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear. In other words, in the fifth combination of the footwear system, each item of footwear comprises two footwear modulators, both of the footwear flexibility modulators disposed in the first configuration of the footwear flexibility modulator.

FIG. 6E shows a sixth combination in which two footwear flexibility modulators are disposed on top of each other inside the upper of the items of footwear (for example between the insole and a removable midsole), with the second surface of one footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear and the second surface of another footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear. In other words, in the sixth combination of the footwear system, each item of footwear comprises two footwear modulators, both of the footwear flexibility modulators disposed in the second configuration of the footwear flexibility modulator.

FIG. 6F shows a seventh combination in which two footwear flexibility modulators are disposed on top of each other inside the upper of the items of footwear, for example between the insole and a removable footbed, with the second surface of one footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear and the first surface of another footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear. In other words, in the seventh combination of the footwear system, each item of footwear comprises two footwear modulators, the uppermost footwear flexibility modulator disposed in the second configuration of the footwear flexibility modulator and the lowermost footwear flexibility modulator disposed in the first configuration of the footwear flexibility modulator. Without wishing to be bound by theory, the seventh combination may allow the foot of a user to bend at the metatarsophalangeal joint region while providing stability and protection from the terrain (for example when stepping on uneven terrain such as branches or stones). This may enable a user to walk comfortably when carrying heavy loads while protecting the feet from the terrain.

Whilst specific embodiments of the present disclosure have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present disclosure. For example, any suitable type of footwear flexible modulators may be used as defined above. Furthermore, the footwear flexible modulators may be formed from any suitable material such as a composite and/or plastics and/or rubber and/or polymeric material. 

What is claimed is:
 1. A footwear system comprising: two items of footwear, one for a left foot and one for a right foot of a user; and at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear, wherein each of the at least two footwear flexibility modulators has a longitudinal axis and a lateral axis perpendicular to each other, the longitudinal axis and lateral axis defining a plane of the footwear flexibility modulator, wherein the plane has a first surface and a second surface; wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction and a second flexural stiffness when bending in a second direction opposite the first direction, and wherein the first flexural stiffness is greater than the second flexural stiffness; and wherein, in use, the footwear system is configured to be worn in one of two configurations: a) a first configuration in which each of the at least two footwear flexibility modulators is disposed in, on or under at least a portion of each item of footwear with the first surface facing towards or substantially towards a collar region of each item of footwear; b) a second configuration in which each footwear flexibility modulator is disposed in, on or under at least a portion of each item of footwear with the second surface of the footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear; wherein the footwear flexibility modulator provides a greater resistance to bending during a gait cycle in the first configuration than in the second configuration; and wherein the footwear system can be reversibly switched from the first configuration to the second configuration by reversing each of the footwear flexibility modulators so that, in use, the opposite of the first or second surfaces of the footwear flexibility modulator faces towards or substantially towards the collar region of the upper of each item of footwear.
 2. A footwear system according to claim 1, wherein the first configuration is a stiff configuration and the second configuration is a flexible configuration when bending the footwear flexibility modulators towards the collar region of the upper of the items of footwear.
 3. A footwear system according to claim 1, wherein the flexural stiffness in the first configuration of the at least two footwear flexibility modulators is at least 2 times greater than the flexural stiffness in the second configuration.
 4. A footwear system according to claim 1, wherein the flexural stiffness in the first configuration of the at least two footwear flexibility modulators is from 2 times to six times greater than the flexural stiffness in the second configuration.
 5. A footwear system according to claim 1, comprising at least four footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear in one of the following combinations: a) Only one footwear flexibility modulator in each item of footwear disposed in the first configuration of the footwear flexibility modulator; b) Only one footwear flexibility modulator in each item of footwear disposed in the second configuration of the footwear flexibility modulator; c) No footwear flexibility modulator located in, on or under at least a portion of each of the two items of footwear; d) Two footwear flexibility modulators disposed on top of each other, the uppermost footwear flexibility modulator in the first configuration of the footwear flexibility modulator, and the lowermost footwear flexibility modulator in the second configuration of the footwear flexibility modulator; e) Two footwear flexibility modulators disposed on top of each other, both of the footwear flexibility modulators disposed in the first configuration of the footwear flexibility modulator; f) Two footwear flexibility modulators disposed on top of each other, both of the footwear flexibility modulators disposed in the second configuration of the footwear flexibility modulator; g) Two footwear flexibility modulators disposed on top of each other, the uppermost footwear flexibility modulator disposed in the second configuration of the footwear flexibility modulator and the lowermost footwear flexibility modulator disposed in the first configuration of the footwear flexibility modulator.
 6. A footwear system according to claim 1, wherein each of the footwear flexibility modulators is shaped to conform to the shape of an insole, midsole or a sole of each of the two items of footwear and wherein, in order to reversibly switch between the first and second configurations, each footwear flexibility modulator is configured to be turned over and disposed in, on or under the other of the two items of footwear so that the opposite layer of the footwear flexibility modulator faces towards the collar region of the upper of each item of footwear.
 7. A footwear system according to claim 1, wherein the at least two footwear flexibility modulators are removable footbeds.
 8. A footwear system according to claim 1, wherein the at least two footwear flexibility modulators are removable inserts configured to be disposed in each item of footwear between a footbed and an insole.
 9. A footwear system according to claim 1, wherein the at least two footwear flexibility modulators are removable inserts configured to be disposed in a recess in the midsole of each item of footwear.
 10. A footwear system according to claim 1, wherein the at least two footwear flexibility modulators are removable inserts configured to be disposed in a recess in a sole of each item of footwear.
 11. A footwear system according to claim 1, wherein each footwear flexibility modulator is a laminate comprising at least a first layer and a second layer, wherein the at least first layer comprises a plate with a modulus of elasticity in the range of approximately 30 ksi-40,000 ksi; and wherein the at least second layer comprises a fiber reinforced material and having a tensile modulus selected from: about 2 ksi to about 3,000 ksi; about 5 ksi to about 2,000 ksi; about 25 ksi to about 1500 ksi; or about 100 ksi to about 2,000 ksi.
 12. A footwear system comprising at least two reversible footwear flexibility modulator inserts, the at least two reversible footwear flexibility modulator inserts comprising at least two layers: a first layer providing an increased bending resistance in a first bending direction relative to a bending resistance in a second bending direction, the second bending direction being opposite to the first bending direction.
 13. A footwear system according to claim 12, wherein the system comprises four footwear reversible footwear flexibility modulator inserts, configured to be inserted in the two items of footwear in one of the following combinations: a) Only one footwear flexibility modulator in each item of footwear with the first layer facing towards or substantially towards an upper of each item of footwear; b) Only one footwear flexibility modulator in each item of footwear with the second layer facing towards or substantially towards an upper of each item of footwear; c) No footwear flexibility modulator located in, on or under at least a portion of each of the two items of footwear; d) Two footwear flexibility modulators disposed on top of each other in each item of footwear, the uppermost footwear flexibility modulator in the first configuration of the footwear flexibility modulator, and the lowermost footwear flexibility modulator in the second configuration of the footwear flexibility modulator; e) Two footwear flexibility modulators disposed on top of each other in each item of footwear, both of the footwear flexibility modulators disposed in the first configuration of the footwear flexibility modulator; e) Two footwear flexibility modulators disposed on top of each other in each item of footwear, both of the footwear flexibility modulators disposed in the second configuration of the footwear flexibility modulator; f) Two footwear flexibility modulators disposed on top of each other in each item of footwear, the uppermost footwear flexibility modulator disposed in the second configuration of the footwear flexibility modulator and the lowermost footwear flexibility modulator disposed in the first configuration of the footwear flexibility modulator.
 14. A process of reversibly modulating the flexibility of footwear, the process comprising: a) providing two items of footwear, one for a left foot and one for a right foot of a user; b) providing at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear, wherein each of the at least two footwear flexibility modulators has a longitudinal axis and a lateral axis perpendicular to each other, the longitudinal axis and lateral axis defining a plane of the footwear flexibility modulator, wherein the plane has a first surface and a second surface; wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction and a second flexural stiffness when bending in a second direction opposite the first direction, and wherein the first flexural stiffness is greater than the second flexural stiffness; and c) disposing at least one of the at least two footwear flexibility modulators in, on or under at least a portion of each item of footwear such that, in use, one of the first surface or the second surface of the footwear flexibility modulator faces towards or substantially towards a collar region of an upper of each item of footwear; d) removing the at least two footwear flexibility modulators from the items of footwear; e) reversing the at least two footwear flexibility modulators; f) disposing the at least two reversed footwear flexibility modulators in, on or under at least a portion of each item of footwear such that, in use, the other of the first surface or the second surface of each of the at least two footwear flexibility modulators faces towards or substantially towards the collar region of the upper of each item of footwear for modifying the flexibility of the item of footwear; and g) optionally, repeating steps d) to f) to revert the flexibility properties of each item of footwear.
 15. A process according to claim 14, wherein each of the at least two footwear flexibility modulators is shaped to conform to the shape of an insole, footbed, midsole or a sole of each of the two items of footwear and wherein, in order to reversibly modify the flexibility of each item of footwear, in step d) each footwear flexibility modulator is removed from one of the two items of footwear and in step e) is turned over and disposed in, on or under the other of the two items of footwear so that, in use, the opposite layer of the footwear flexibility modulator faces towards or substantially towards a sole of a foot of the user.
 16. A process according to claim 14, wherein each of the at least two flexibility modulators is an insert configured to be disposed in an item of footwear between an insole and a footbed and in steps c), f) and g) it is disposed inside each item of footwear directly on a midsole.
 17. A process according to claim 14, wherein each of the at least two flexibility modulators is a sole attachment and in steps c), f) and g) it is disposed in a recess in a sole of each item of footwear.
 18. A process according to claim 14, wherein the process comprises providing four footwear reversible footwear flexibility modulator inserts, configured to be inserted in a pair of items of footwear in one of the following combinations: a) Only one footwear flexibility modulator in each item of footwear in the first configuration of the footwear flexibility modulator; b) Only one footwear flexibility modulator in each item of footwear in the first configuration of the footwear flexibility modulator; c) No footwear flexibility modulator located in, on or under at least a portion of each of the two items of footwear; d) Two footwear flexibility modulators disposed on top of each other in each item of footwear, the uppermost footwear flexibility modulator in the first configuration of the footwear flexibility modulator, and the lowermost footwear flexibility modulator in the second configuration of the footwear flexibility modulator; e) Two footwear flexibility modulators disposed on top of each other in each item of footwear, both of the footwear flexibility modulators disposed in the first configuration of the footwear flexibility modulator; e) Two footwear flexibility modulators disposed on top of each other in each item of footwear, both of the footwear flexibility modulators disposed in the second configuration of the footwear flexibility modulator; f) Two footwear flexibility modulators disposed on top of each other in each item of footwear, the uppermost footwear flexibility modulator disposed in the second configuration of the footwear flexibility modulator and the lowermost footwear flexibility modulator disposed in the first configuration of the footwear flexibility modulator.
 19. A process according to claim 14, wherein the flexural stiffness in the first configuration of the at least two footwear flexibility modulators is at least 2 times greater than the flexural stiffness in the second configuration.
 20. A process according to claim 14, wherein the at least two footwear flexibility modulators are laminates comprising at least a first layer and at least a second layer, wherein the at least first layer comprises a plate with a modulus of elasticity in the range of approximately 30 ksi-40,000 ksi; and wherein the at least second layer comprises a fiber reinforced material and having a tensile modulus selected from: about 2 ksi to about 3,000 ksi; about 5 ksi to about 2,000 ksi; about 25 ksi to about 1500 ksi; or about 100 ksi to about 2,000 ksi. 